The determination on what is and is not sufficient conditioning is highly dependent on where/what you need conditioning in/for. For you, jump rope may be sufficient, or it may be completely inadequate.
As an example: I'm a strongman recovering from ACL reconstructive surgery. For me, jumping rope would not be sufficient, as it would re-aggravate my injury, and wouldn't contribute anything to my strongman training. This means that my conditioning is pulling a prowler arm over arm with some very light uphill pushes. Other people may need to perform some slam ball slams to improve their explosiveness, or run hills, or hit a tire with a sledgehammer, etc etc.